27 coins and the Grocer
The Grocer decides to check the coins , however another customer is in a hurry and says that he will leave if it takes too much time. The Grocer has only a pan balance ( two sided weighing scale which compares the weights and shows the heavier one).
how many times does he have to weigh the coins at minimum?
*If one coin is disturbed, touched,removed,moved,added to the pan balance etc it counts as one weighing. *Assume that the magician is telling the truth i.e. one coin is slightly heavier and fake *Assume that the rest of the coins weigh exactly same.